In radio frequency (RF) communications, coverage and capacity can be improved through the use of spatial diversity or spatial multiplexing. For example, using spatial multiplexing, data rates can be increased by transmitting independent information streams from different antennas but using the same channel as defined by frequency and time resources.
These systems are referred to as multiple input multiple output (MIMO) systems. Typically, MIMO systems require complex controllers to control both the transmission and receiving elements of the mobile station and the base station.
Multi-stream single user MIMO transmission has been proposed and forms part of Wideband Code Division Multiple Access (WCDMA), Third Generation Partnership Project-Long Term Evolution (3GPP LTE), and WiMax system standards. In single user multiple input multiple output (SU-MIMO), a MIMO receiver with multiple antennas and receiving circuitry receives the multiple streams, separates the multiple streams and determines the transmission symbols sent over each stream of the spatially multiplexed data streams.